CIVIL ENGINEERING FORMULAS

HYDRAULICS AND WATERWORKS FORMULAS 327

or (12.107)

Withg32.16,

(12.108)

Parabolic Channels

These channels can be conveniently defined in terms of the top width Tand the
depthDc. Then the area a DcTand the mean depthDm.
Then (Fig. 12.21),

(12.109)

and (12.110)

Further, (12.111)

Withg32.16,

(12.112)

and (12.113)

Also, (12.114)

Withg32.16,

Q2.005TH (12.115)

3/2

m

Q

B

8 g

27 

3

4 

3/2

TH3/2m

Dc

3

2 B

3 Q^2

gT^2

Q3.087TD3/2c

Q

B

8 g

27

TD3/2c

Dc

3

2

V^2 c

g

Vc^2  3 gDc

(^2) 
3
Q2.295zHm5/2

Q

B

g

2 

4

5 

5/2

zHm5/2

T

Dc

FIGURE 12.21 Parabolic open channel.